Hydraulic gripper for derrick skidding



sept. 2, 1969 H. B. 'CHAMBERS 3,464,095

HYDRAULIC GRIPPER FOR DERRICK SKIDDING Filed Feb. 19, 1968 9 f FOOT OF ONE/1"` CORNER OF Il n DERRICK I3 I4 la F C f' :Ev-r? 42 sHlM 2 v1, fZO

F22 No 221A@ HENRY B. CHAMBERS INVENTOR VBY ATTORNEY United States Patent O HYDRAULIC GRIPPER FOR DERRICK SKIDDING Henry B. Chambers, Santa Barbara, Calif., assignor to Hydronautics, Santa Barbara, Calif., a corporation of California Filed Feb. 19, 1968, Ser. No. 710,432 Int. Cl. B66c 23/60 U.S. Cl. 24-263 7 Claims ABSTRACT F THE DISCLOSURE A pair of C shaped or channel shaped gripper members lit over the outer edges of a flange of an I beam which supports a sliding oil derrick. The gripping of the I beam is accomplished by a flattened tube lying inside each channel member. Fluid is pumped under pressure into the tubes which tend to assume a round cross section, pressing against the I beam and one rib of the channel members. This causes the other rib of the channel member to be pressed tightly against the I beam flange, giving rise to a powerful gripping action. A hydraulic motor connects the channels to the derrick, and the channels act as an anchor against which the derrick can be pushed or pulled. The cross plate connecting the channel members is large enough to adjust the channels to different Widths of l beams.

Disclosure My invention relates to grippers of the type that do not damage or scar the object being gripped and has special reference to a fluid powered gripper using flattened ilexible tubes as the gripper motor.

In some types of oil well installations, for example, in marine drilling from artificial islands, platforms or anchored vessels, a single derrick is used to drill or service a large number of individual wells. This requires the derrick to be moved from one location to another. While rails and wheels are sometimes used for such movement, the deeper wells and larger wells require a much more substantial footing to carry the large bearing loads. For this purpose large, flat-topped steel beams are used which are generally I beams or H beams. A pair of spaced I beams each support two legs of the derrick, thus giving very solid support to the usual four legged oil derrick.

The derricks are skidded or slid along the supporting I beams by grippers that engage the I beam and are connected by a motor to one leg or foot of the oil derrick. When energized, the gripper acts as an anchor against which the derrick is pushed or pulled. At the end of the stroke of the motor, the gripper is de-energized, and the motor operated to pull or push the gripper ot a new anchoring position. In this fashion the gripper inches its way along an I beam, pushing or pulling the derrick with it to the desired location.

Formerly ratchet devices were employed that required notches or holes in the steel surfaces of the I beam in order to get a positive bite. These, however, scarred and roughened the supporting surface and tended to weaken the I beam. There were superseded by the frictional type of gripper using compression of the flange only and one such type is shown in Patent 3,373,971, issued Mar. 19, 1968. The present invention provides a gripper of this frictional type employing a simplified design which has an extremely powerful gripping action.

A general object of my invention is to provide an irnproved hydraulic gripper for oil derrick skidding.

Other objects, advantages and features of the invention will be apparent in the following description and claims 3,464,095 Patented Sept. 2, 1969 considered together with the accompanying drawing forming an integral part of this disclosure in which:

FIG. l is a three dimensional view of an I beam supporting one corner of an oil well derrick and having a gripper embodying the invention attached to the I beam and connected by hydraulic motor to the oil derrick foot.

FIG. 2 is a plan view of the gripper of FIG. l.

FIG. 3 is an end view of the gripper of FIG. 2 partly in section taken along the line III-III of FIG. 2.

FIG. 4 is a plan view of a shoe forming part of the gripper and illustrated as being the shoe for the upper longitudinal member as viewed in FIG. 2.

Referring to FIG. 1 there is illustrated an I beam 10 which supports two legs of an oil derrick, and there is illustrated a foot 11 on only one of such legs designated by the numeral 9. The function of the gripper of the invention is to slide the foot 11 along the I beam 10 in either of 2 directions. The gripper of the invention is designated by the numeral 12, and it grips the outer edges of the upper flange of the I beam 10. A hydraulic piston-cylinder motor interconnects the gripper 12 and the foot 11, so that the foot can be pushed or pulled. Accordingly, a cylinder 13 has a piston rod 18 projecting from one end, and this terminates in a elevis 16 which is connected to the foot 11 by a pin 17. The other end of the cylinder 13 is connected by a pin 19 to the gripper 12. Fluid under pressure is passed into ports 14 in the cylinder 13 to cause the piston rod 18 to move in one direction or the other, to thereby move the foot 11.

Referring now to all of the figures, the gripper preferably engages both of the outer edges of the upper flange of the I beam 10. These are designated in FIG. 3 by the numeral 23. Accordingly, a pair of identical channel members 20 having inwardly projecting ribs 21 and 22 are passed over the outer edges 23 of the flanges to partly encircle these flanges. The two channels 20 are secured on the flange edges 23 by a cross plate 30 having a pair of upwardly projecting spaced lugs 31 through which the pin 19 passes to secure the cylinder 13 to the gripper. Bolts 32 pass through the plate 30 to fasten the channel members 20 in the correct spacing so they will engage the outer flanges 23 as shown in FIG. 3. Various sets of holes 33 may be provided in the cross plate to lit I beams of differing width.

Referring now particularly to FIG. 3, there is illustrated a shoe 24 which bears directly on the upper surface of the flange edge 23 and disposed on this shoe 24 is a flattened flexible tube 26, formed of any high strength tubular material, such as reinforced rubber or rubber like materials. Disposed above the flattened tube 26 is a bearing strip 27 against which the tube 26 presses when fluid under pressure is introduced into the tube. A pair of side plates 28 may be welded or otherwise secured to the bearing strip 27 to project below it to contain the tube 26 directly underneath the bearing strip 27. A shim 29 may be disposed between the bearing strip 27 and the upper rib 21 of the channel member 20. A bolt 34 may secure the shim 29 and the bearing strip 27 in position. Diierent thicknesses of shim 29 may be employed, so that the channel 20 can properly llt over I beam flanges of different vertical thickness, as viewed in FIG. 3.

The tubes 26 may be terminated by suitable metal llttings 36 which include a transverse plate 37 which plate is bolted to the enlarged end portion of the bearing strip 27. In this fashion the flattened tubes 26 are stretched between the ends of the bearing strip 27. A suitable hydraulic tting 3S may be connected to the metal fittings 36, and a pressure tube 39 may interconnect both tubes, as shown best in FIG. 2. Accordingly, the tube 39 may be connected to a source of lluid under pressure, for example, a hydraulic pump or an accumulator, and in this fashion fluid under pressure is forced inside the ICC ilattened tubes 26, causing them to tend to assume a round cross section, which in turn presses against the shoe 24 and the bearing strip 2,7, to grip the ange edge 23 tightly.

As shown best in FIG. 4, the shoe 24 has enlarged ends. While both chanel members 20 and constituent assemblies are identical, for ease of reference the shoe of FIG. 4 will be referred to the upper channel 20 of FIG. 2. Referring to FIG. 4, the shoe 24 has on its upper side a pair of upwardly projecting ears 41 formed one on each end. A distance D between these two ears 41 is identical to the longitudinal length of the channel member 20. AC- cordingly, the shoe 24 cannot slip lengthwise with respect to the channel member 20, because these ears 41 interlock the two members together. The shoe 24 is prevented from slipping sideways of the channel 20 by a pair of bolts 42 passing through two smooth bores in the enlarged bearing strip ends 27, to be threaded into threaded holes 40 in the ears 41 and in opposite ears 43 of the shoe 24. lnasmuch as the tubes 26 must assume a generally round condition at their ends to be gripped by the metal fittings 36, the shoe 24 may have a tapered portion 44 at each end to allow for this more circular condition of the tubes 26 compared to the flattened cross section shown in FIG. 3. If desired, the end portions of the bearing strip 27 may be similarly tapered to accommodate this -rounded cross section near the ends of both of these strips.

Channel members 20 extend along beam 10 for a considerable distance. This allows the gripping forces produced within the gripper to be distributed over a large surface of the iiange, thus, allowing a frictional grip of the iange and preventing the llange from being marred. Since the tlange is not marred or deformed by the gripper, the derrick easily slides over the I beam. The length of channel members 20 should be sufficient to prevent deformation of the beam when the beam is gripped between shoes 24 and channel ribs 22.

When it is desired to remove the entire gripper from the I beam and replace it at another point or on another I beam, it is highly desirable to eliminate much of the remaining iluid in the flattened tubes 26. While the weight of the gripper tends to flatten these tubes, sometimes trapped uid causes the gripper to engage the flange edges 23 sufficiently tightly so that it is desirable to compress the tube 26 mechanically. For this purpose the bolts 42 are tightened, thus pulling the shoe 24 towards the bearing strip 27, which in turn is held in position by the bolts 34. To prevent bowing of the shoe 24 during this operation, this tightening can `be effected at an intermediate point, and for this purpose there is illustrated in FIG. 4, a lug 46 disposed at an intermediate point, and, it too has a tapped hole 40 formed in it. As shown in FIG. 2, this lug 46 is disposed underneath the cross plate 30, and accordingly the bolt 42. at that location bears against the cross plate 30 when it is turned to lift the center section of the shoe 24.

Operation When it is desired to move the foot 11 of the oil derrick shown in FIG. 1, uid under pressure is applied to the conduit 39 shown in the left hand part of FIG. 2. This causes uid to enter the ilattened tubes 26, shown in the right hand part of FIG. 3. The tubes tend to assume a rounded cross section, pushing upwardly on the upper rib 21 of the channel 20 and pushing downwardly on the shoe 24, thus compressing the ange edge 23 between the shoe 24 and the lower channel rib 22. In this fashion both channels 20 of the gripper securely engage the I beam 10, and it acts as an anchor against which the oil derrick may be pushed or pulled.

To etect movement of the oil derrick foot 11, tluid under pressure is introduced to one of the ports 14'in the cylinder 13 shown in FIG. 1. This causes the piston rod 18 to extend or contract pushing or pulling the foot 11 accordingly. When the piston-cylinder motor 13-18 has reached the limit of its stroke, the uid under pressure in the flattened tubes 26 is then released so that the tubes assume their flattened condition illustrated in FIG. 3. Appropriate pressure fluid is then introduced to the ports 14 of the cylinder 13, causing it to push or pull the gripper 12 along the I beam in the desired direction. In this instance, the great weight of the derrick foot 11 and the lack of resistance of the gripper allows the derrick foot 11 to act as the anchor for the movement of the gripper. The gripper is then re-energized to again assume its anchoring action, and the piston-cylinder motor 13-18 is again actuated. In this fashion the gripper can inch along the I beam 10, pushing or pulling the derrick foot 11 with it.

It will be seen with reference to FIG. 3, that during these pushing and pulling operations on the derrick foot 11 that the shoe 24 will be subject to longitudinal stresses. The shoe 24 takes up the longitudinal stresses by the terminal ears shown best in FIG. 4 wherein the ears 41 are spaced apart the same distance D as the length of the channel 2 0, and accordingly, interlock the shoe 24 with the channel 20.

When it is desired to remove the entire gripper from an I beam, the bolts 42 at each end of the bearing strips 27 are tightened, pulling the shoe 24 upwardly as best shown in the left part of FIG. 3 and in FIG. 4. An intermediate bolt 42 threaded into a lug 46 (FIGS. 1 and 4) bears against the cross plate 30 to pull up an intermediate part of the shoe 24. In this fashion suicient clearance is obtained to tit the gripper over the outer edges 23 of an I beam ange.

When it is desired to t the gripper over an I beam having a different vertical thickness of ange 23, as viewed in FIG. 3, a diterent thickness of shim 29 is inserted in the assembly to accommodate for this difference in thickness. When it is desired to ft the gripper to an I beam having a different horizontal width of I beam flange, then the bolts 32 in the cross plate 30 are placed in different holes 33 corresponding to the different width of the I beam.

It will be appreciated by those skilled in the art that various modifications can be made in the gripper mechanism without departing from the true spirit and scope of the invention. For example, it is readily apparent that one channel member 20, or equivalent C-shaped member could be used instead of a pair of members. Further, it is readily apparent that these members need not be straight, but can be curved to fit any particular surface desired. Any type of motor can interconnect the gripper and the object to be moved. It is also obvious that the shims and bearing strips could be dispensed with and the tube could bear directly against a rib of the channel member.

For these and various other reasons the invention is not limited to the specific embodiment illustrated but includes all variations and modiiications that fall within the true spirit and scope of the invention.

I claim:

' 1. A gripper for gripping a anged member comprising:

(a) a pair of elongated channels each having spaced ribs to t over the flanges of the member;

(b) a cross plate connecting the two channels;

(c) a flexible attened tube in each channel disposed between one rib of the channel and the ange to be gripped; and

(d) means for connecting the attened tubes to uid under pressure, said flattened tubes tending `to assume a round cross section under pressure to move one rib of the channel away from the ange to thereby cause the other rib to press against the tiange to grip it.

2. A gripper as set forth in claim 1 wherein a shoe is disposed in each channel between the tube and the flange and is interlocked with the respective channel against longitudinal movement, whereby longitudinal forces applied to the gripper are absorbed by the shoe and the tube is free of them.

3. A gripper as set forth in claim 2 wherein mechanical means are provided for moving each shoe toward said one channel rib so that clearance may be obtained by compressing the exible tube so that the entire gripper may be moved off or on a flange of a member.

4. A gripper as set forth in claim 1 wherein a shim is disposed between the tube and the one rib of each channel so that the channels can accommodate anges of different thickness.

5. A gripper for a ilange as set forth in claim 4 wherein said cross plate is adjustably connecting the two channels together to accommodate flanged members of different width.

6. A gripper for a flange as set forth in `claim 1, wherein a shoe is disposed between the tube and the flange and means are provided to mechanically interlock the shoe and channel against relative longitudinal movement.

7. A gripper for a ange comprising:

(a) a member of channel shaped cross section having spaced parallel ribs to fit over the flange to be gripped and having a longitudinal shape to fit the ange outline, said member extending along the length of said flange for a suicient distance to allow 25 the gripper to engage the ange with a frictional grip;

(b) a attened tube disposed within the channel to bear against oney channel rib and the ange to be gripped;

(c) and means for connecting the flattened tube to fluid under pressure, whereby said llattened tube tends to assume a round cross section under pressure, pushing said one channel rib away from the ange being gripped, causing the other channel rib to be pressed against the ilange to compressively grip it with a frictional grip thereby not deforming the ange.

References Cited UNITED STATES PATENTS 2,382,958 8/1945 Burgoine et al. 2,394,785 2/ 1946 Kindervater. 3,033,525 5/ 1962 Johnson 254-107 DONALD A. GRIFFIN, Primary Examiner U.S. Cl. X.R. 254-107 

